The broad, long-term objective is to develop and market a system of three- dimensional radiation dosimetry for radiation therapy treatment quality control. Radiation therapy requires that radiation dose be applied to target sites in the body, while sparing adjacent, healthy tissue. To accomplish this, therapists make use of treatment-planning computers to predict the detailed distribution of radiation dose. There is a need for an independent measurement check on such plans to verify the actual radiation dose delivered by the plan. The potential technological innovation consists of a translucent, colorless, tissue-equivalent gel that develops a stable color in response to and in proportion to radiation dose delivered locally. In Phase I we have demonstrated such a gel, and employed our optical scanner to record the color distribution in three dimensions. We intend to develop this into a marketable product, by addressing the following Specific Aims: A. Further develop our scanning technology by improving the software for data acquisition, analysis and report presentation. B. Further develop our scanning technology by improving the hardware, especially the optics and mechanical drive components. C. Develop a continuous or semi-continuous process for gel production D. Optimize radiation sensitivity, resolution and accuracy of the gel dosimetry system. E. Obtain outside feedback on the dosimeter's utility from the potential medical community. We envision the potential commercial application as a dosimetry service to hospitals and medical centers. . Radiation treatment for cancer and other conditions involves exposing humans to potentially hazardous high energy radiation. This research and development effort will result in a device that will provide therapists with a visual check that the planned pattern of radiation is suitable for the patient. This device will therefore reduce the potential for unwanted and unnecessary radiation doses to the patient. It involves a colorless gel that can be exposed to the planned radiation; the gel develops color, showing the pattern of radiation dose actually delivered. [unreadable] [unreadable] [unreadable]